Storm's Dominant Role On The Depostition And Erosion Evolution In The Yellow River Delta

The Yellow River Delta is under unique geographic environment that storm surges frequently happen there. It's one of the worst storm hazard areas in China and also in the world's. The storm surges happened in the Yellow River Delta have brought huge losses. Funded by the National High Technology Research and Development Program of China, this paper carried out the following research.(1) Researched the storm surge effects on evolution of erosion and deposition on the northern part of the abandoned lobe in Yellow River Delta. More than 10 field survey data were used to compare the impact of conventional factors (wave, tidal, etc.) and compare storm surges, using software such as GIS and Matlab. The effect levels were introduced with quantitative indicators and geomorphological dynamics theory.(2) The subaqueous delta evolution of erosion and deposition deduced by storm surge on the Yellow River was researched. Using the 14 surveying lines data in 20 years, observed by the Yellow River Water Resources Survey Bureau of the Yellow River Delta data, and combined EOF & ANN model, the erosion and deposition amount were recalculated in the years with storms. The results were compared with the measured values to extract the effect of storm surges on the Yellow River subaqueous delta; and then related mechanisms were discussed.After the study, conclusions are as follows:(1) storm surges have significant effect on the northern beaches of the Yellow River Delta abandoned lobe. From the data measured in Chezigou, the role of one storm surge is more than the whole year's erosion and deposition changes caused by conventional factors, which proved that storm surges on the northern abandoned lobe of the Yellow River Delta plays a controlling role in its evolution.(2)Processing the data of water depth on the yellow river delta, the variation of erosion and deposition in the storm tide years was obtained. Comparing with the measured value, it was found that the storm tide played a great role in the erosion and deposition evolution of the yellow river delta especially in the area which is 15km away from the shore. Although the role we found was great, the result it caused which is erosion or deposition is not certain. According to the analyze to the three storm tide, the influence can be intense erosion or intense deposition or even indistinctive. So it cant't give an quick answer that what kind of influence is the storm tide on the yellow river delta.(3) The mechanism of erosion on the yellow river deta caused by storm tide which is obtain in this article is consistency with other scolar's idea that it is the sediment transport caused by the storm that make the yellow river delta erode. But the mechanism of dispositon on the yellow rive delta is not very clear. So a hypothesis is proposed in this article that if the direction of the storm tide which is belong to a high-energe incident is shoreward, it can take lots of seawater which contains a high sand density which can't be taken away by the bottom flux to the shore, the dispositon happens.(4) The phenomenon that erosion in north and deposition in south, this may be mainly because circumfluence caused by storm is strengthened, which makes the sands that eroded from the northern Yellow River Delta or newly deposited in the estuarine are transported to the southern of Yellow River Delta. Whereas the phenomenon that erosion in shore and deposition off shore is mainly due to transport sands alongshore caused by storm.